The present invention relates to improved solutions for processing dynamo-electric machine components (e.g., armatures or stators for electric motors, generators, or alternators) through resin application process steps.
Resin application steps are common in the manufacturing of dynamo-electric machine components. The dynamo-electric machine components such as armatures include insulated wire coils wound on ferromagnetic cores. Electric current passes through the wire coils in the operation of the dynamo-electric machine in which the component is used. For optimal performance of the dynamo, the dynamo-electric machine components' wire coils may be subject to tight dimensional tolerances. However, the wires in the coils, which are mechanically wound, are susceptible to loosening due to vibration or heat during further manufacturing or assembly steps. Operation of the dynamo-electric machine itself also may cause vibrations and heat, which tend to loosen the wire coils. Electrical current, which passes through the wire coils, also may generate electromechanical forces that tend to loosen or deform the wire coil shapes. To avoid distortion of the wire coil dimensions due to these or other causes, the wires in a coil are customarily coated and encased in a hard bonding material matrix such as a hardened resin coating. The hard resin coating mechanically stabilizes the wire coil by binding the wires in the coil together and thereby preventing relative movement of the wires. Additionally, the resin coating provides a heat conduction path to dissipate heat generated in the wires. The resin coating also protects the wire insulation from abrasion during further steps of the manufacturing process and during the operation of the dynamo-electric machine.
The resin coating process steps are carried out in the dynamo-electric machine component manufacturing process using resin application stations. The resin application stations may, for example, include resin impregnation machines in which liquid dispensers trickle liquid resins on to the wire coils. The dispensed liquid resin impregnates the wire coils by filling up interwire spaces, for example, by capillary action. Alternatively, resin impregnation machines may dip the wire-coil components in liquid baths to coat the wires with liquid resin. A resin application station usually also involves additional machines such as preheating units for preparing the dynamo-electric machine components for liquid resin impregnation, and resin-curing machines for curing or hardening the impregnated liquid resin.
In the resin-curing or hardening machines, the impregnated liquid resins, which generally are polymeric materials, are converted from a liquid state to a three-dimensionally cross linked hard solid state by chemical (polymerization) reactions. These chemical reactions are temperature dependent. Often the resin curing reactions are effective only in a narrow range of elevated temperatures. The resin curing machines used in the dynamo-electric manufacturing processes usually are heating furnaces or ovens. Dynamo-electric machine components having wire coils impregnated with liquid resin are heated in the ovens and held for a time period at the elevated “curing” temperatures. The quality of hardening or curing of the impregnated resin may depend on amount of time the resin temperature is within a narrow range of curing temperatures. Non-uniform temperatures across the impregnated resin on a dynamo-electric machine component may adversely affect the quality the hardened resin coating. Further, component-to-component differences or variations in heating may adversely affect manufacturing process uniformity and reproducibility, which are desirable for commercial production.
Consideration is now being given to ways of providing solutions for improving dynamo-electric machine component manufacture. Attention is directed toward preheating units and curing units, with a view to improve the resin coating process, and to improve the overall efficiency of dynamo-electric machine component manufacturing.